Effect of background colors on the tuning of color-selective cells in monkey area V4
Effect of background colors on the tuning of color-selective cells in monkey area V4
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DOI：
10.1152/jn.00597.2005
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发表时间：
2006-05-01
影响因子：
2.5
通讯作者：
Zeki, S
中科院分区：
文献类型：
--
作者：
Kusunoki, M;Moutoussis, K;Zeki, S
当在不同光源下观察物体时，尽管从物体反射的光的波长组成发生了显着变化，但它们的颜色不会改变或变化很小。在之前的研究中，我们通过记录麻醉猴子 V1、V2 和 V4 区域的细胞，解决了这种颜色恒常性背后的生理学问题。真正的颜色编码细胞只在 V4 区域中发现，这些细胞对给定颜色的色块做出反应，而不管从该色块反射的光的波长组成如何。在本研究中，我们使用了不同的方法来测试麻醉和清醒行为猴子中 V4 细胞的反应。嵌入蒙德里安型彩色背景中的不同颜色的刺激用于识别神经元的颜色选择性。然后改变背景照明，并针对每个背景照明再次测试 V4 神经元的调节。对于麻醉的猴子，改变背景照明的心理物理效应是根据我们自己的经验推断出来的，而在清醒的行为动物中，它是由猴子直接报告的。我们发现，大多数 V4 神经元都会随着背景照明的每次变化而改变其颜色调节配置文件：每次改变计算机屏幕上的背景颜色以模拟照明的变化时，细胞都会将其颜色调节功能向色度分量增加的方向移动。在人类和猴子的颜色匹配样本心理测量功能中也观察到类似的变化。猴子心理测量功能的变化在数量上相当于相应细胞群反应的变化。我们得出的结论是，V4 区的神经元表现出颜色恒定性，因此它们的响应特性能够反映颜色感知。
When objects are viewed in different illuminants, their color does not change or changes little in spite of significant changes in the wavelength composition of the light reflected from them. In previous studies, we have addressed the physiology underlying this color constancy by recording from cells in areas V1, V2, and V4 of the anesthetized monkey. Truly color-coded cells, ones that respond to a patch of a given color irrespective of the wavelength composition of the light reflected from it, were only found in area V4. In the present study, we have used a different approach to test the responses of V4 cells in both anesthetized and awake behaving monkeys. Stimuli of different colors, embedded within a Mondrian-type multicolored background, were used to identify the chromatic selectivity of neurons. The illumination of the background was then varied, and the tuning of V4 neurons was tested again for each background illumination. With anesthetized monkeys, the psychophysical effect of changing background illumination was inferred from our own experience, whereas in the awake behaving animal, it was directly reported by the monkey. We found that the majority of V4 neurons shifted their color-tuning profile with each change in the background illumination: each time the color of the background on the computer screen was changed so as to simulate a change in illumination, cells shifted their color-tuning function in the direction of the chromaticity component that had been increased. A similar shift was also observed in colored match-to-sample psychometric functions of both human and monkey. The shift in monkey psychometric functions was quantitatively equivalent to the shift in the responses of the corresponding population of cells. We conclude that neurons in area V4 exhibit the property of color constancy and that their response properties are thus able to reflect color perception.